1. Field of the Invention
The invention relates to axial piston rotary power device having one or more pistons disposed parallel to and displaced from an axis of rotation. More particularly, the invention relates to internal combustion engines, pumps, compressors, expanders and fluid motors. It additionally relates to any two such devices that differ in a simple structural modification of a central cylindrical stationary member.
2. Background Information
This invention relates to rotary power devices of the type having a plurality of cylinders arranged around and parallel to a central axis of rotation in an equally-spaced relationship, and in which pistons disposed within the cylinders cooperate with a cam track to impart rotational motion to a rotor when the pistons reciprocate in their respective cylinders. Examples of rotary devices of the above type can be found in United States patent specifications such as U.S. Pat. No. 5,813,372 of Manthey; U.S. Pat. No. 4,287,858 of Anzalone; U.S. Pat. No. Re. 30,565 and U.S. Pat. No. 4,157,079 of Kristiansen; U.S. Pat. No. 5,209,190 of Paul; U.S. Pat. No. 5,103,778 of Usich, Jr.; U.S. Pat. No. 5,253,983 of Suzuki, et al.; U.S. Pat. No. 5,323,738 of Morse; U.S. Pat. No. 4,213,427 of Di Stefano; and U.S. Pat. No. 1,614,476 of Hutchinson. Although such power devices have been proven to be theoretically functional, they are characterized in some respects by complexities associated with the arrangements of cams and of intake and discharge means, which make them costly to manufacture, assemble, and maintain.
An axial piston rotary power device of the invention comprises a stator portion and a rotor portion that has a rotatable shaft extending along an axis of the device. The stator portion of the device comprises an external stator portion defining a generally cylindrical interior bounded by a back plate portion and a front plate portion that has a central throughhole within which the rotatable shaft is journaled. In addition, the stator comprises a cylindrical internal stator portion projecting from the back plate portion into the cylindrical interior along the axis of the device so as to define an annular space extending between the internal and external stator portions. The internal stator portion has a plurality of passageways within it, each of the passageways comprising a channel parallel to the axis and each of the channels communicating with at least one respective radially oriented port formed in the internal stator at a respective selected axial position. Yet another static portion of the device is an axially undulating guide track surface that may be incised into an internal wall of the external stator portion, or that may be formed from separate tubular elements fixedly attached to either the front or back plates. The rotor portion of the device comprises a cylindrical block fixedly attached to the shaft arid rotatable within the annular space between the internal stator portion and the guide track surface. This block has a central cylindrical bore adapted to receive the internal stator, and also includes a selected number of working cylinders parallel to the axis of the device. Each of the working cylinders is spaced apart from the axis of the device by a single selected radial distance, and each of the working cylinders has a radially inwardly directed end opening adjacent each of its two ends. One of the end openings of each cylinder communicates with the central cylindrical bore at a first of the selected axial positions, the second of the end openings of each cylinder communicates with the central cylindrical bore at a second of the selected axial positions. In addition, each of the working cylinders also has a respective axial cam follower slot extending outwardly through an outer wall of the cylindrical block. Each of the cylinders has a respective piston slidably received within it, and each of the pistons is connected to a respective cam follower by means of a respective pin extending outwardly through the respective cam follower slot. All of the cam followers engage the undulating guide surface so as to couple a rotary motion of the block to the reciprocating translational motions of the pistons. If the pistons are driven to and fro within the cylinders by known means such as the expansion of an explosive air-fuel charge, or by the introduction of a pressurized working fluid, the rotary power device of the invention can function as an internal combustion engine or as a fluid-driven motor or expander providing output shaft power. Conversely, if the block is rotated by the application of a torque to the input shaft, the rotary power device of the invention can function as a pump or compressor.
One embodiment of the present invention provides an improved spark ignition rotary internal combustion engine which operates in a four-cycle mode and which overcomes problems presently encountered in the class of rotary engine having pistons positioned parallel to each other around a common axis of rotation. Another embodiment of the present invention provides an improved rotary internal combustion engine which operates in a two-cycle mode and which overcomes problems presently encountered in the class of rotary engine having pistons positioned parallel to each other around a common axis of rotation.
A preferred embodiment of the invention provides a rotary power device having valveless ports.
A feature of some embodiments the invention is that they are light in weight, small in size and have a reduced part count when compared with prior art rotary power devices.
Another feature of a preferred rotary power device of the invention is that it can be easily converted to another type of rotary power device by a simple modification or replacement of a central stationary member. Thus, one can convert an internal combustion engine of the invention into a rotary power device that can act as any one of a pump, a compressor, a fluid-driven pump, a fluid-driven compressor and a fluid-driven motor.
A benefit of some embodiments of the invention is that they provide a rotary power device that closely approximates continuous intake, compression, combustion and discharge processes.
Another benefit of some embodiments of the invention is that they provide a rotary power device characterized by reduced noise and vibration.
Although it is believed that the foregoing recital of features and advantages may be of use to one who is skilled in the art and who wishes to learn how to practice the invention, it will be recognized that the foregoing recital is not intended to list all of the features and advantages. Moreover, it may be noted that various embodiments of the invention may provide various combinations of the hereinbefore recited features and advantages of the invention, and that less than all of the recited features and advantages may be provided by some embodiments.